CUSTOMIZABLE SOFT PNEUMATIC GRIPPER DEVICES

Master'sMASTER OF ENGINEERIN

A WEARABLE FOOT MOTION TRACKING SENSOR FOR OUTDOOR RUNNING

Throughout human history, running has evolved from a form of locomotion to a recreation or competitive pursuit. The purpose of this project was to develop a foot motion tracking sensor using inertial measurement unit (IMU) to determine the running kinematics of the ankles of individuals under different external or physical conditions such as change in directions, running on slopes or level ground or fatigue. These results may be helpful in providing a real-time quantitative data, which will be useful for runners to monitor their training programs and routes. The preliminary results showed that the system can detect ankle dorsiflexion/plantarflexion across different route condition, where these results can be used for further analysis such as designing a training program and monitoring the fatigue level

BIOMECHANICS OF RUNNING WITH FOREFOOT-SPRING FOOTWEAR

Forefoot strikers have significantly lower rates of repetitive stress injury than rearfoot strikers. The purpose of this study was to design a forefoot-spring footwear to induce habitual rearfoot runners to adopt a forefoot strike pattern and to investigate the effect of this forefoot-spring footwear on lower extremity joints biomechanics during running. Our findings indicated that different lower limb energy absorption strategies were adopted for running with the forefoot-spring footwear, as compared to control footwear. A shift from hip-dominant to ankle-dominant energy absorption strategy may reduce the loading to the hip and knee joints and could be beneficial towards the prevention of running related injuries particularly at the knee joint

DEVELOPMENT OF A WEARABLE GAIT DETECTION SYSTEM FOR RACEHORSES

Biomechanical analysis of racehorses is important in quantifying and maintaining performance. Early detection of lameness is crucial to ensure the wellbeing and proper rehabilitation of horses, and to prevent exacerbation of the condition. The purpose of this study was to develop a limb-mounted portable wireless sensor system to investigate equine biomechanics and detect the presence of lameness in racehorses based on the lower limb kinematics. The preliminary results showed that the system can detect trotting gait cycles accurately and the lame racehorse showed a reduction in hoof flexion and extension as compared to normal racehorse

Investigation of the biomechanical effect of variable stiffness shoe on external knee adduction moment in various dynamic exercises

10.1186/1757-1146-6-39Journal of Foot and Ankle Research61

Design and Evaluation of a Novel Hybrid Soft Surgical Gripper for Safe Digital Nerve Manipulation

Forceps are essential tools for digital nerve manipulation during digital nerve repair surgery. However, surgeons have to operate forceps with extreme caution to prevent detrimental post-operative complications caused by over-gripping force. Their intrinsically safe characteristics have led to the increasing adoption of soft robotics in various biomedical applications. In this paper, a miniaturized hybrid soft surgical gripper is proposed for safe nerve manipulation in digital nerve repair surgery. This new surgical gripper includes a soft inflatable actuator and a gripper shell with a hook-shaped structure. The ability to achieve a compliant grip and safe interaction with digital nerves is provided by the inflated soft pneumatic actuator, while the rigid hook retractor still allows surgeons to scoop up the nerve from its surrounding tissues during surgery. The performance of the proposed surgical gripper was evaluated by the contact/pulling force sensing experiments and deformation measurement experiments. In the cadaver experiments, this new surgical gripper was able to complete the required nerve manipulation within the limited working space. The average deformation of the digital nerve with an average diameter of 1.45 mm gripped by the proposed surgical gripper is less than 0.22 mm. The average deformity is less than 15% of its original diameter

Three-Dimensional Printable Ball Joints with Variable Stiffness for Robotic Applications Based on Soft Pneumatic Elastomer Actuators

This paper contributes to a new design of the three-dimensional printable robotic ball joints capable of creating the controllable stiffness linkage between two robot links through pneumatic actuation. The variable stiffness ball joint consists of a soft pneumatic elastomer actuator, a support platform, an inner ball and a socket. The ball joint structure, including the inner ball and the socket, is three-dimensionally printed using polyamide−12 (PA12) by selective laser sintering (SLS) technology as an integral mechanism without the requirement of assembly. The SLS technology can make the ball joint have the advantages of low weight, simple structure, easy to miniaturize and good MRI compatibility. The support platform is designed as a friction-based braking component to increase the stiffness of the ball joint while withstanding the external loads. The soft pneumatic elastomer actuator is responsible for providing the pushing force for the support platform, thereby modulating the frictional force between the inner ball, the socket and the support platform. The most remarkable feature of the proposed variable stiffness design is that the ball joint has ‘zero’ stiffness when no pressurized air is supplied. In the natural state, the inner ball can be freely rotated and twist inside the socket. The proposed ball joint can be quickly stiffened to lock the current position and orientation of the inner ball relative to the socket when the pressurized air is supplied to the soft pneumatic elastomer actuator. The relationship between the stiffness of the ball joint and the input air pressure is investigated in both rotating and twisting directions. The finite element analysis is conducted to optimize the design of the support platform. The stiffness tests are conducted, demonstrating that a significant stiffness enhancement, up to approximately 508.11 N·mm reaction torque in the rotational direction and 571.93 N·mm reaction torque in the twisting direction at the pressure of 400 kPa, can be obtained. Multiple ball joints can be easily assembled to form a variable stiffness structure, in which each ball joint has a relative position and an independent stiffness. Additionally, the degrees of freedom (DOF) of the ball joint can be readily restricted to build the single-DOF or two-DOFs variable stiffness joints for different robotic applications

Shape Programming Using Triangular and Rectangular Soft Robot Primitives

This paper presents fabric-based soft robotic modules with primitive morphologies, which are analogous to basic geometrical polygons—trilateral and quadrilateral. The two modules are the inflatable beam (IB) and fabric-based rotary actuator (FRA). The FRA module is designed with origami-inspired V-shaped pleats, which creates a trilateral outline. Upon pressurization, the pleats unfold, which enables propagation of angular displacement of the FRA module. This allows the FRA module to be implemented as a mobility unit in the larger assembly of pneumatic structures. In the following, we examine various ways by which FRA modules can be connected to IB modules. We studied how different ranges of motion can be achieved by varying the design of the rotary joint of the assemblies. Using a state transition-based position control system, movement of the assembled modules could be controlled by regulating the pneumatic pressurization of the FRA module at the joint. These basic modules allow us to build different types of pneumatic structures. In this paper, using IB and FRA modules of various dimensions, we constructed a soft robotic limb with an end effector, which can be attached to wheelchairs to provide assistive grasping functions for users with disabilities